Ly Thi Vang, a second grader, smiles during a painting test. She has been living at the school with her teachers after both of her parents were arrested for drug trafficking.

Na U Commune is only 40 kilometers from Dien Bien Phu, the capital town of Dien Bien Province in northern Vietnam, but few drivers would take the road as they are scared of the heroin stigma.

Years ago, many people in the commune had engaged in drug trafficking to China. Some of them managed to build villa houses, buy cars and other luxury items, but most just went to jail before any good things happened when police started to track down the operation in 2010.

A number of primary school teachers have devoted many years of their life to the commune, getting no pay for taking care of their wards even after working hours because many pupil's parents have to spend time in jail or at rehab centers.

Some teachers have been with the commune for 19 years, and the newest ones have been there for four years.

Vu Van Dao, the school principal, said "The commune's primary school has 210 students. 83 of them are from families involving some form of drug abuse, and about 40 have parents jailed for drug trafficking."

The school was not built for boarding purposes, but it turned into one when the children had no parents left to take care of them, Dao said.

One of the children is Ly Thi Vang, a second grader.

"Both of her parents have been arrested for drug trafficking, so she spends all the time at the school," Dao said.

Vang's father was jailed before she was born, and she was at class when her mother was arrested.

Her teachers said one of her brothers had came to Vang's class and told her, and the girl just ran out of the room and ran behind the car carrying her mother.

She was crying a lot and skipped class for two weeks, before returning with all her clothes and books. She said she wanted to stay at school with the teachers.

The parents of Sung Thi Si, a first grader, were arrested the same day as Vang's mother.

"There were nights they had fever, they kept calling their mothers in their dreams and the pillows were soaked with tears," said Ngo Thi Vieng, a teacher.

Vieng has been teaching at the commune for ten years.

She said few teachers chose the school, despite its higher allowances, as they're uncomfortable with it being a heroin hotspot.

But Vieng said she was not attracted by the allowances. She used to teach at a school for ethnic minority people in the province, and knows several languages. She can communicate well with children and families in Na U commune, most of whom from the Mong ethnic group.

Many children at the school are also children and grandchildren of her former students, so she can easily persuade the families to send the children to school, Vieng said.

"It's like seeing my acquaintances again," Vieng said.

She and 26 other teachers at the school are busier than their colleagues elsewhere, having to prepare three meals for the children, wash their cloths, and bathe the little ones.

At night, the youngest children, Si and Vang, are allowed to sleep with a female teacher.

"The kids really love their teachers," said Dao, the principal.

None of the children have dropped school because they receive enough care now, he said.

But the teachers are still struggling to improve their care. They are having to donate their own money for the children's meals as financial support from the province's agencies is not stable.

"Each of us gives around VND200,000 a month so that the children's meals are not too simple," said Mac Van Uc, a male teacher.

But for now, the teachers and students have to make do with frugal meals. They can only afford cheap ingredients like tofu, which show up in most of the meals.